secret service agent who walked ahead of president obama during "the nine" inaugural parade and he knows what it takes to secure this type of situation. dan, that's what people want to know. how? how could this happen? >> good question. i think everybody is assuming, though, that these bombs were planted yesterday when they, in fact exploded and the event happened. that may not be the case. i don't know that for a fact, but what concerned the secret service and me specifically when i was there and we would organize the parade route for the president was not a device trying to come in that day. we knew we would be able to intercept it, but a device that was preplanted. and that, unfortunately, may be an avenue they may have to pursue investigatively. >> brian: from what you can tell, from what we know, this saudi national is a person of interest in the hospital right now who we've gone through his apartment. how unusual is it for the bomber, who is not a homicide bomber, to be a victim? evidently he had burns on him and smelled like gun powder. what does that make you conclude? >> yeah. u